Ophthalmological fixation lamp assembly

ABSTRACT

This invention relates to a fixation lamp assembly for an ophthalmological instrument, having a head rest for a patient, a light collimator, and bearing means disposed between the head rest and the collimator allowing adjustment of the collimator relative to the head rest about at least two axes intercepting the optical axis of the collimator in the center of rotation of an eye of the patient. Thus the patient is able to recognize the fixation mark of the collimator in any position within his field of vision with ease and uniform quality, without turning his head.

United States Patent [1 1 Papritz et al.

[451 Mar. 18, 1975 OPHTHALMOLOGICAL FIXATION LAMP ASSEMBLY [75]lnventors: Hans Papritz, Liebefeld; Kurt Hagi,

Niederwangen, both of Switzerland 73] Assignee: Haag-Streit AG, Bern,Switzerland [22] Filed: Apr. 17, 1973 [2i] Appl. No.: 351,847

[30] Foreign Application Priority Data Apr. 24, I972 Switzerland 6025/72[52] U.S. Cl 351/37, 248/288, 35l/38 [5|] Int. Cl A6lb 3/00 [58] Fieldof Search 35l/l, I3, 30, 36, 37, 351/17, 38; 248/288 [56] ReferencesCited UNITED STATES PATENTS 3,201.795 8/1965 Cuppers et al 351/383,475.075 [0/1969 Stone,Jr 351/38 X 6/197l Gambs 351/] X OTHERPUBLICATIONS William Dale, Fixation. examination," J. Amer. Optom.Assoc., Vol. 30, No. l2, pp. 869-870, July 1959.

Primary Examiner-Paul A. Sacher Attorney, Agent, or Firm-Imirie, Smiley& Linn (57] ABSTRACT This invention relates to a fixation lamp assemblyfor an ophthalmological instrument, having a head rest for a patient, alight collimator, and bearing means disposed between the head rest andthe collimator allowing adjustment of the collimator relative to thehead rest about at least two axes intercepting the optical axis of thecollimator in the center of rotation of an eye of the patient. Thus thepatient is able to recog nize the fixation mark of the collimator in anposition within his field of vision with ease and uniform quality.without turning his head.

9 Claims, 6 Drawing Figures PATENTEUMAM 8I975 5,871,753

sum a 95 3 OPHTHALMOLOGICAL FIXATION LAMP ASSEMBLY This inventionconcerns an ophthalmological fixation-lamp assembly movable about atleast two different axes while maintaining proper focal alignmentrelative to the eye of a patient. A fixation lamp is typically used tofix the direction of sight of the eye of a patient so as to facilitateophthalmological examination. The patient should be able to recognize afixation-mark, photograph, or other indicia of the fixation lampthroughout his field of vision with ease and similar quality, withoutturning the head. This is obtained according to the present invention inthat a collimator is hinged around two axes which intersect thecollimator optical axis in the center of motion of the eye.

The invention will be explained in detail by referring to the attacheddrawings, which show an example of a preferred embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a side elevational view of afixation lamp assembly according to the present invention;

FIG. 2 is a partial top plan view with parts broken away of the guide ofthe fixation lamp assembly looking in the direction of the arrow II inFIG. 1;

FIGS. 3 and 4 are partial sectional views of details of the assembly ofFIG. 1',

FIG. 5 is a partial sectional view taken along line V\/ in FIG. 4; and

FIG. 6 is a partial view taken along line VI-VI in FIG. 2.

DESCRIPTION OF THE INVENTION The shown fixation-lamp is attached to aholder, from which two lateral supports I and 2 are shown. Thesesupports are fixed on a table or the like, which is not represented. andon which an instrument, for instance a slitlamp, may also be attachedfor examining an eye of the patient. The patient can put his foreheadagainst a ribbon or head support band 3, which is connected with thesupports 1 and 2. By using the head support 3, the position of the eyes,from which one (4) is schematically drawn in FIG. 1, may beapproximately determinated relative to the holder and its supportedfixation lamp.

The holder has a yoke 5 which extends between the ends of the supportsand in which a carriage 13 can be moved along a straight guide. To thiscarriage is fixed an extension arm 6 having parts 6a and 6b which areconnected by a vertical-axial joint 7. At the lower end of support part6b a bent, substantially L-shaped collimator 8 is hingedly mounted onbearings. and contains a lamp 4] and a fixation-mark, whose image can beviewed through a lens 9 and a mirror 10. As FIG. 1 shows, the axis A ofthe joint 7 axis B, of the bearing of the collimator 8, and axis C ofthe lens 9 intersect at the center of rotation of the eye 11.

FIGS. 2, 4 and 6 show the construction of the straight guide for thefixation lamp. Between the side flanges of yoke 5 is fixed a guide bar12, on which the carriage 13 is exactly guided along axial bearings. Thecarriage is secured against swinging around guide bar 12 by bearingswhich run in a groove 14 of yoke 5. The bearings 15 are excentricallyfixed on pivots 16 (FIG. 6) which are disposed in holes and are securedagainst rotation by screws 17. When the screws are loosened, the pivots16 can be rotated until the bearings 15 rest against the walls of thegrooves to guide the carriage without play in the desired position. Thenthe screws can be fastened. The carriage is provided with adjustablestops 18, which determine the limits of travel.

At the rear panel of yoke 5 is fixed a stoprail 19 with two stoprecesses or detents 20. At the carriage is located an index roller 21,which cooperates with the stop recesses and determines either of twopositions of the carriage in front of the respective eyes of thepatient. The inclined edge-surfaces l9a of the stop rail l9 areexplained below.

At the rear panel of yoke 5 is also fixed an insulated rail 22, which isconnected with a conductor 25 which passes through the support I. Aspring-loaded, insulated brush 24, which is located in the support part6a pushes at one end against the rail 22 and is connected at the otherend by a biasing spring to a conductor 25, which is located in the armsupport 6.

The joint 7 of arm 6 (FIGS. 4 and 5) has a plate 26 which is connectedwith support part 60 and a plate 27. which is connected to support part6b. On the hub 28 of plate 26 is pivoted a disk 29, which is connectedto plate 27 and presses against a friction liner 31 under the action ofstar-spring 30which is also mounted on hub 28. Thus parts 60 and 6b arehingedly connected. but the turning movement can only be transmitted byovercoming a certain amount of friction.

The collimator 8 (FIG. 3) is attached over a tube 32 and secured with abolt 33 and nut 34 which a slot in the end of the collimator. The tube32 is pivoted in a bore of the lower, enlarged end of part 6b. It has agroove 35 accommodating a springloaded ball 36. This ball causes acertain friction in the pivot bearing oftube 32 and, because of thesmall distance to the pivot 46. prevents axial displacement. Theconductor 25 is guided over a terminal and a springloaded brush 37 to aslipring 38 which is fastened in an insulated manner on tube 32. Theslipring has an external insulation layer 39 which serves as anoperating handle for the turning of tube 32 and collimator 8. Theslipring is connected by a threaded member, which is disposed in thehollow operating handle, to an insulated spring-loaded contact 40, whichis inside tube 32. This contact 40 is connected over a common spring toa spring-loaded contact 42 which presses against the central pin of lamp41.

In the collimator 8 is a tube 43 which can be adjusted with knob 44 inan axial direction and which remains in the adjusted position byfriction. In the front end of tube 43 is disposed on opaline body 45having a fixation mark. The zero position of tube 43 is chosen such thatthe fixation mark is in the focal point of lens 9. A normal-sightedpatient sees the image of the fixation mark at infinity. For near or farsighted patients the fixation mark can be adjusted by the handle withthe aid ofa scale (not shown) on collimator 8, so that the mark appearsin focus.

In operation, the patient places his forehead against band 3 and hischin on an optional chin support (not shown). The carriage I3 is thenmoved to a detentdetermined position in which it is approximatelyaligned over the patient s eye which is not to be exam ined. When theillumination is on. the current for the lamp 4] flows over conductor 23.rail 22. brush 24. conductor 25, brush 37. slipring 38. contacts 40 and42, and lamp 4] to ground. The examiner can then fully control eyeposition for substantially the entire range of eye movement providedaxis A of joint 7 and axis B of the collimator go through the center ofrotation 11 of the eye. An eventual correction can be made through aslight lateral displacement of the head of the patient, for example. byvarying the height of the chin rest. As the two cited rotation-axes gothrough point 11 of the eye, the fixation mark is visible to the patientat all positions ofjoint 7, as well as collimator 8, if lens 9 is in hisfield of vision. This condition is fulfilled at a minimum angle of 45between the horizontal rotation axis B and the optical axis C. The eyeto be examined follows the movements of the eye which looks at thefixation mark and stays in the fixed direction during examination. Forthe examination of the other eye the carriage is displaced by the meaneyes-distance to the other stopposition. The adjustment is the same asdescribed above.

When the fixation lamp is not used, the carriage is moved over thestop-position on one side, to an endposition, which is determinated bythe stops 18, whereupon the index roller 21 comes to rest on one of theinclined edge-surfaces 19a of stop rail 19 and thus secures thecarriage. With fine adjustment of the stops it is possible to determineexactly the end positions.

It is possible to change details of the above described fixation lamprelative to the shown embodiment. Thus, support part 6a may not befastened to a carriage which can be moved along yoke 5, but can behinged directly to the yoke with a joint similar to joint 7. This jointhas preferably means for stops. which determines two rotationalpositions of part 6a. so that axis A ofjoint 7 goes through one of botheyes of the patient for each of those turning positions. If necessary,part 60 can be made to swing past the stop position of the joint in twopositions of rest, if the fixation lamp is not used. The resistance inthe stop positions of part 6a must be such, that part 6h can be turnedaround without turning part 60 out of its stop position.

What is claimed is:

1. An ophthalmological fixation lamp assembly, comprising a head-restfor a patient; a light collimator having an optical axis; bearing meanscoupling said collimator to said head-rest for movement of saidcollimator about a plurality of axes intercepting one another at aposition corresponding to the center of rotation of an eye of thepatient, said bearing means constraining the optical axis of saidcollimator to pass through said position of interception independentlyof the position of said collimator about said plurality of axes wherebysaid eye may be fixed at any position while the other eye of the patientis examined; said bearing means ineluding guide means disposed over saidhead-rest for enabling horizontal movement of said collimator relativeto said head-rest for bringing the collimator in front ofeither eye ofthe patient; said guide means having a guide element fixedly attachedover said head rest, and carriage means movable along said guideelement; and said bearing means having a first arm extending from saidcarriage means, and a second arm pivotally connected with said first armfor rotation about one of said plurality of axes; said collimator beingpiv otally coupled to said second arm for rotation about another of saidplurality of axes.

2. The fixation lamp assembly according to claim I wherein said secondarm is provided with an insulated brush connected to a source ofoperating potential. and said collimator is provided with an annularelectrical contact cooperating with said brush to provide said potentialto said collimator.

3. The fixation lamp assembly according to claim 1 wherein saidcollimator extends from one side of said second arm and includes a knobextending from the opposite side of said second arm to facilitaterotational positioning of said collimator and said plurality of axes.

4. The fixation lamp assembly according to claim 1 wherein said guidemeans further comprises means cooperating with said carriage means todetermine the horizontal position of said collimator in front of theeyes of the patient.

5. The fixation lamp assembly according to claim wherein one of saidplurality of axes is horizontal and another is vertical.

6. The fixation lamp assembly according to claim wherein said collimatorhas fixation indicia and means for moving said indicia in bothdirections out of the focal point of the collimator lens.

7. The fixation lamp assembly according to claim I. wherein said guideelement is provided with an insulated rail, electrically connected to asource of operating potential, said rail being in contact with a brush.which is electrically connected to said collimator.

8. The fixation lamp assembly according to claim 1 wherein said guidemeans includes stop means cooperating with said carriage means todetermine rest and end positions of said carriage means outside an operation range.

9. The fixation lamp assembly according to claim 1 wherein said opticalaxis of said collimator is obliquely disposed relative to said pluralityof axes.

1. An ophthalmological fixation lamp assembly, comprising a head-restfor a patient; a light collimator having an optical axis; bearing meanscoupling said collimator to said head-rest for movement of saidcollimator about a plurality of axes intercepting one another at aposition corresponding to the center of rotation of an eye of thepatient, said bearing means constraining the optical axis of saidcollimator to pass through said position of interception independentlyof the position of said collimator about said plurality of axes wherebysaid eye may be fixed at any position while the other eye of the patientis examined; said bearing means including guide means disposed over saidhead-rest for enabling horizontal movement of said collimator relativeto said head-rest for bringing the collimator in front of either eye ofthe patient; said guide means having a guide element fixedly attachedover said head rest, and carriage means movable along said guideelement; and said bearing means having a first arm extending from saidcarriage means, and a second arm pivotally connected with said first armfor rotation about one of said plurality of axes; said collimator beingpivotally coupled to said second arm for rotation about another of saidplurality of axes.
 2. The fixation lamp assembly according to claim 1wherein said second arm is provided with an insulated brush connected toa source of operating potential, and said collimator is provided with anannular electrical contact cooperating with said brush to provide saidpotential to said collimator.
 3. The fixation lamp assembly according toclaim 1 wherein said collimator extends from one side of said second armand includes a knob extending from the opposite side of said second armto facilitate rotational positioning of said collimator and saidplurality of axes.
 4. The fixation Lamp assembly according to claim 1wherein said guide means further comprises means cooperating with saidcarriage means to determine the horizontal position of said collimatorin front of the eyes of the patient.
 5. The fixation lamp assemblyaccording to claim 1 wherein one of said plurality of axes is horizontaland another is vertical.
 6. The fixation lamp assembly according toclaim 1 wherein said collimator has fixation indicia and means formoving said indicia in both directions out of the focal point of thecollimator lens.
 7. The fixation lamp assembly according to claim 1,wherein said guide element is provided with an insulated rail,electrically connected to a source of operating potential, said railbeing in contact with a brush, which is electrically connected to saidcollimator.
 8. The fixation lamp assembly according to claim 1 whereinsaid guide means includes stop means cooperating with said carriagemeans to determine rest and end positions of said carriage means outsidean operation range.
 9. The fixation lamp assembly according to claim 1wherein said optical axis of said collimator is obliquely disposedrelative to said plurality of axes.